Pitch Perfect
by deichtine
Summary: A suspicious package delivered to the Eppes home forces Charlie to walk a mile in Don’s shoes as he must investigate its origins, while Don deals with a frustrating case. Nonship, multipart WIP. Chapter 5 is now up!
1. It's a what?

**Disclaimer:** _NUMB3RS_ and its associated characters, etc., belong to the show's creators and to CBS, wonderful people whom I have never met and have no connection to. I hope they don't mind me using them here; no legal infringement intended.

**Spoilers: **Anything from all aired episodes is fair game. This is AU in the sense that Terry is still here.

**Rating:** K+ - may have minor language later on, and themes I don't think kids need to worry themselves with.

**Relationships:** This isn't a shipper fic, but there will be some 'romantic' issues that, to tell you too much would ruin the story. But suffice it to say, it won't be Charlie/Amita. ;) We may get some D/T hints but they'll be minor.

**Summary:** A suspicious package delivered to the Eppes home forces Charlie to walk a mile in Don's shoes as he must investigate its origins.

**Thanks:** To my beta-readers! You guys are the greatest. Also to the sources from which I'm pulling information, which I'll acknowledge chapter by chapter via footnote.

**Author's Note:** I've noticed that at least two of the best stories out there ongoing right now for _NUMB3RS_ are so good mostly because the people writing them really know what they're talking about and are integrating detail by writing what they know (I'm thinking of sammac's "Skewed" and Julie Cidell's "Shifting Ground"). I'm going to try to write about things I know a little about, viz. language and music, and we'll see if I can do half so well.

One thing I know nothing about is police/FBI procedures for handling suspicious packages - so I'm going to guess the best I can and if you have some advice I'd be glad to hear it. I tried to do some research but found very little. I think in real life they'd probably take it to a contained area, but I've chosen to do it this way to advance the plot.

Also, I promise subsequent chapters will have far less lengthy pre-story ramblings. :D

**Pitch Perfect**

by Deichtine

The doorbell rang, jerking Charlie from his state of total concentration. He rubbed the bridge of his nose and sighed, not noticing that he was leaving a pale streak of chalk dust behind. He put down the chalk, automatically wiping his hands on his pants, and skipped down the stairs, committing what he could of his train of thought to memory so as to minimize the effect of the interruption.

The man standing on his step was a UPS courier, blinking in the broad sunlight of the beautiful day, bouncing idly on his toes as he waited for the door to open. When Charlie came to the door, the man held out a small box-shaped package and a clipboard. "Delivery for Donald Eppes," he said, sounding a little bored.

Charlie accepted the package, signed for it, and brought it inside. He set it on the coffee table, making a mental note to call Don after work, and ascended the stairs again, his mind already several steps ahead, in the solarium with the chalkboard.

It wasn't until the rumbling in his stomach became too insistent to ignore that he began to notice that the light in the room was different - the sun was now shining on the opposite side of the house - and a significant amount of time had passed. He checked his watch, and was startled to see that it was well past time to start preparing supper; Dad would be home from his committee meeting for the community association soon and Charlie had promised to have supper ready.

He put his chalk down again, and stepped back to survey his work. Not bad. Larry would be pleased; so far the math was backing up his theory one hundred per cent. He picked up the little digital camera from the side table and snapped some pictures of the chalkboards, so as to be sure not to lose anything he'd done, and stretched.

"Charlie?" Don's voice came calling from downstairs, and Charlie startled mid-stretch. He hadn't heard his brother come in.

"Upstairs, Don. I'll be down in just a second." Charlie looked at his ghost-like, chalk-covered hands and decided to stop by the washroom on his way down.

"Hey, Charlie, what's this -----" Don's words were obscured by the running water.

"Just a minute Don, can't hear you." Charlie turned off the tap. "Okay, what?"

"What's this box thing?"

Charlie came down the stairs, still drying his hands on his shirt. "I don't know. It came for you this morning. UPS." Don was staring at the box as though it were a poisonous snake.

"Who from?" Don was now circling the package, bending over now and then, looking for a return address; there was none. Charlie noticed that his brother had not yet once touched the box.

Charlie shrugged. "How should I know? You know, you're around here enough already without having your mail sent here, too." He grinned to let Don know he was teasing, but Don didn't seem to hear the comment; he was motioning Charlie to shush as he held his ear closeto the box, listening.

"Well, it's not making any noise. Was it heavy?"

Charlie thought for a moment. "I don't remember. Kind of, I guess. Not excessively. Why don't you just pick it up?"

Don looked at him as if he were crazy. "Because, Charlie, I don't know what it is, who it's from, or why it's here. It could be anything, and I'm not going to move it any more than I have to. Excuse me." Don stood up and grabbed the phone. "Hi, this is Agent Don Eppes. I'm at my brother's home and I've got a suspicious package that was delivered for me at this address, and I'd like to have it checked out..." he gave the person at the other end the address and relevant information, while Charlie just stared.

"Don, don't you think you're overreacting a little? It's probably just your birthday sweater from Aunt Eliza; we got mail here for you for months after you left for university."

"It's not from Aunt Eliza. Aunt Eliza wouldn't send a sweater by UPS, and definitely not by the UPS agent you saw, who wasn't a UPS agent at all. Come on, let's move to the kitchen until they get here."

"Why do you say that?"

"Because, if there is something harmful in that package, I'd like to be away from its general vicinity."

"No, no, why do you say the guy wasn't from UPS?"

"The package was totally mislabeled. None of the correct information was there. There's no way UPS would have accepted it, much less delivered it. Did you sign for it?"

Charlie nodded. "Yeah."

Don thought for a second. "Well, I don't know what harm that could do. But we might need you to give a description of the guy."

"Well, I'll try, but I wasn't really paying attention. He interrupted me when I was working, and I barely registered his coming."

Don sighed. "Well, just think about it, remember what you can. Okay?"

Charlie nodded. He stood up, got himself and Don each a glass of water, and sat down again, and they sipped in silence, both a little tense.

"Don, do you really think that package might be dangerous?" Charlie asked at last. "Cause, you know, I just bought the house and really don't want my living room blown up yet..." The joke was half-hearted at best, but Don smiled and shook his head.

"To tell you the truth, I don't think the package itself is going to blow up, no. But I just don't think it can mean anything good. The fact that it's here, its implications worry me. If someone with a grudge against me looked me up he'd find my apartment address, right? So why was the box delivered here? Only the people who know me would know how much time I spend here."

Charlie thought about that, deeply troubled. "Are you sure it's aimed at you?"

"It was addressed to me, wasn't it?"

"But that could be meant to throw you off. Maybe it was aimed at me."

Don looked at Charlie skeptically. "Charlie, who would want to hurt you? You're a math prof, for heaven's sake, and your students like you, don't they?"

Charlie nodded. "Seem to."

"You're about as innocuous as they come. I, on the other hand, have been in charge of putting criminals behind bars, more than one for sending incendiary devices through the mail." Don stood up as the doorbell rang. "They're here. Let's find out what's in this thing."

David Sinclair led the team of Hazardous Goods personnel who entered the Eppes living room, suited and gloved. Charlie hung back, quietly observing as Don went forward to greet his teammate.

"David, man, thanks for coming. I didn't realize you were on this team."

David shrugged. "I'm not, usually. But I have the training, and Briggs was sick tonight, so I got called as backup. This the package?"

Don nodded. "That's it."

David crouched to look at it. "What tipped you off?"

"Wasn't expecting anything, certainly not here. There's no return address, and you can tell the handwriting is deliberately being disguised. The guy who brought it was dressed like UPS but it's not marked right for it. It just rang alarm bells."

David nodded. "Yeah, I can see that. Good call." Without further ado, he and his team went to work.

Most of the devices they used to check the package without opening it Charlie had never seen before, and he had to resist the urge to push in for a better look. He found it interesting to see how the FBI approached the "black box" scenario, and what methods they used to look inside without looking inside. He thought about mentioning Schrodinger's cat, thought better of it.

Finally, after much careful scanning, wiping, inch-by-inch examination, listening and other tests, David very carefully cut the tape holding the outer paper packaging together and allowed it to fall away gently, revealing a plain, polished walnut rectangular box, no more than three inches high and five wide.

"It's a music box."

Don's face betrayed his confusion, and he stepped forward to look more closely. "It's a what?"

"A music box. Give me a second and I'll show you." David examined the crack between the lid and the rest of the box, looking for any kind of leaking powder or liquid. Finding it clean, he went through the scanning procedures again. Finally, believing it to be safe, the agent wound the mechanism with the key at the back, and opened the lid.

A tinkling sound filled the suddenly quiet room, but it was not long before the expressions on the faces of the agents present turned from focussed concentration to confusion. The sound that filled the air was not truly music; there were different pitches, but the rhythm was off, and seemed to be accented oddly. Short bursts of notes were separated by brief rests.

"What the...?" David said as the sound wound down. "Did that sound like music to you?"

"Not exactly Beethoven," Don agreed. "Charlie, any ideas?" David began carefully dusting the box for fingerprints.

Charlie was surprised. Why was Don asking him? "No, I'm just as surprised as you are. Do you think the music itself might be a code?"

Don raised an eyebrow. "Well, that's kind of what I'm asking you."

Charlie shrugged. "I suppose it could be. It doesn't sound like a tune."

"You want to take it, see whether you can find a pattern there?"

"Um, don't you need to take it as evidence or something? Try to track it?"

Don shook his head. "Now that we've made sure that it's not dangerous, there's no case. Just because someone decided to send me a music box and stay anonymous - there's no actual crime in that. If they had sent me a controlled substance or a weapon, that's different, but this is just a music box, no matter how weird. So FBI resources can't really be spent on it until we have reason to believe it's attached to a larger case. As you said, this _could_ just be some wacky present from Aunt Eliza." The tone of his voice said he thought it was anything but. "Though, if you can avoid actually taking it apart, or damaging it, it might not be a bad idea."

"Oh." David, now finished his dusting, passed the box to Charlie, who took it gingerly in the palms of his hands, feeling the grit of the leftover dust against the smoothness of the wood.

"Any prints?" Don asked, and David shook his head.

Charlie looked at his brother. "So we're on our own with this?"

"If you're willing to take a crack at it."

Charlie stared at the music box with mixed feelings. It would be an interesting problem, and a good chance to work one-on-one with Don on a project outside his work, but something just didn't feel right, something he couldn't quite define. He sighed.

"Well, okay. Why not?"

End Chapter 1.

Find a fun and interesting explanation of Schrodinger's cat at h t t p / w w w. bbc. co. uk /dna /h2g2 /A1073945 (take out all the weird spacing) - I've linked to it from my author profile too.


	2. The Crunchy Kind

**Disclaimer:** _NUMB3RS_ and its associated characters, etc., belong to the show's creators and to CBS, wonderful people whom I have never met and have no connection to. I hope they don't mind me using them here; no legal infringement intended.

**Author's Note:** Here comes chapter two! As always, I welcome feedback, especially constructive criticism. Thank you beta readers - you're my chocolate milk.

**Pitch Perfect - Chapter 2**

by Deichtine

Alan came into the kitchen to find his two sons sitting hunched over the table, talking softly.

"Sorry I'm late, Charlie. Mrs. MacPhee decided to filibuster. Hey Don. So what's for supper?" Alan put his folder of community association paraphernalia on the counter and, realizing he hadn't received an answer, turned to look more closely at what his sons were looking at with such intensity. When he recognized the object as decidedly not food, he sighed.

"Ah, so I see we're having music boxes tonight," he said, unfazed. "I hope you got the crunchy kind, because I'm starved."

"What?" Charlie finally looked up at his father, taking a moment to shift mental gears and process the remark. Supper. He was supposed to make supper.

"Oh, Dad, I'm sorry. I for - I mean, I didn't forget. Well - not at first, but with the bomb squad and everything -"

"Bomb squad?" Alan interrupted. He turned on his older son, alarmed. "Don, is this your doing?"

"Not exactly." Don's voice was calm, reassuring. "Someone sent an anonymous, unmarked package here today, and I was a little -"

"Paranoid?" Charlie jumped in, helpfully.

"No!" Don gave his brother a look. "I was _cautious_ because I have been _trained_ to recognize suspicious packages, and this fit the bill to a T. So I had the guys come over to check it out."

"And it was a music box?" Alan asked.

"Yeah. So, false alarm for now, but I, for one," - at this he looked again at Charlie, who was smiling behind his glass of water - "happen to think that, considering my job, it's better to be a little overcautious than seriously injured."

Alan made a conciliatory gesture. "Well, I'm just glad it _was_ a false alarm. So let's hear it."

"Hear what?" Charlie asked, with genuine puzzlement.

"The song. It does play music, doesn't it?"

"Oh," Charlie said, a little embarrassed. Of course. He wound the mechanism and allowed the box to play its weird, staccato song for his father. When the box wound down, Alan hrumphed dismissively.

"Doesn't sound like much, does it? Is it broken or something?" he asked, as he pulled a box of spaghetti noodles out of the cupboard.

"Well, that's what we've been trying to figure out," Don said, taking a moment to massage his eyes. "The barrel thing, the thing with all the little tines, and the winding mechanism look fine, though we'll have to take it apart - maybe take it to an expert - to be sure."

"But first," Charlie said, "we're going to have to make some good quality recordings, get the notes transcribed, and see if there's anything to be learned from the music."

"I presume that's where you come in," Alan said, putting the water on to boil.

"Yeah. So, sorry about supper. I've been a little preoccupied."

"No problem. I can see how a visit from the bomb squad and the appearance of an unexplained, unmusical music box would disrupt your plans."

"Hazardous materials, not bomb squad," Don corrected.

Alan ignored him; he was searching the cupboards. "Where's the tomato sauce?"

Charlie froze. "Oh, um, yeah. Tomato sauce. That would require grocery shopping, wouldn't it?"

Alan looked at his apologetic younger son, sighed, and put the spaghetti noodles away.

* * *

Don arrived at work the next morning tired and grumpy, and not at all enthusiastic at the ribbing he was sure to get for calling the dangerous goods guys out the previous night on a false alarm. He and Charlie had been up until midnight with the music box, Charlie playing that stupid song-that-wasn't-a-song again and again as he watched the rotating cylinder, attempting to chart the little bumps on paper so he could start the pattern analysis. Don had spent the time trying to think - when he could think at all, with the music box playing almost continuously - of names, listing people who might have reason to want to get back at him, then people who might be playing a practical joke on him, then people who might have honestly wanted to send him a gift. The first list was depressingly longer than the others. 

"Morning, Don."

"Morning, Terry." The petite blonde entered the elevator just before the doors closed, and positioned herself across from him.

"So, I hear you had a bit of a scare at your place last night."

"Well, technically at my dad's - I mean, Charlie's place. False alarm. So how'd you hear about it?"

"You'd be surprised how fast news travels when dangerous goods personnel are called from their evenings at home to another agent's house for an impromptu gift opening." Don opened his mouth to defend his actions, but she stopped him with a raised hand. "Don't worry, Don, nobody blames you. From what I'm told, the package _was_ pretty suspicious looking, and the tech guys agreed with your decision to call them in. They're just pissed off at the jerk who sent it to you."

Don nodded, mollified. "Yeah, well, they're not alone in that."

They stepped off the elevator and passed one by one through the security door to their office area, flashing their passes to the door guard.

"So what was it, anyway?"

"A music box."

Terry's eyebrows rose. "Really?"

Don made a face. "Well, more accurately, a 'varied pitch sounds' box, as Charlie put it, 'cause what it's playing sure isn't music; it's all just jumbled notes. It reminds me of when Charlie was two and mom would sit him in her lap at the piano, and he'd hit random keys." He paused, remembering. "You know, even then he was kinda different. Most kids that age want to bang on the keys with the whole hand, make a lot of noise. Charlie wanted to hear each note distinctly."

"So do you have any idea who sent it yet?"

"No, not really. I'm gonna take a look at my recent cases, see if anything pops, but frankly I don't know how much I'll find. It's pretty much out of the blue. And I have a mountain of reports to go through for this case."

"What about tracing the box itself?"

"Charlie's looking into that today."

* * *

Charlie pushed open the door to the little antique shop, a bell tinkling to announce his arrival, and wondered again how he had been conned into spending his class prep day biking, bussing, and taxi-ing around the closer parts of Los Angeles looking for antique and hobby shops. He didn't mind the exercise particularly, or the fare, but it was difficult to navigate traffic or watch for his bus stops and mark his students' proofs simultaneously. He had a feeling he would be giving his new TA something of a 'baptism by fire' tomorrow. 

"Good morning, sir," said the man behind the counter brightly. Tall and slender, he had that particular combination of rimless glasses, English accent, and attitude of willing, cheerful service that was at once reassuring and vaguely intimidating. "How might I be of service?"

Charlie reached into his backpack, pulled out the (carefully wrapped) box, and set it on the counter. "I was wondering what you might be able to tell me about this," he said, as he pulled the wrapping away to reveal the polished wood. "It was...given to my family, but we don't know anything about where it comes from. Mark, at Roarke's Antiques, said that there was someone here who has a particular interest in music boxes, and might be able to point me in the right direction."

"Did he, now!" The man looked as pleased as though Charlie had just given him a birthday present. "He was indeed correct. I have some small knowledge of the craft. Let's have a look."

He took the box in the tips of his long fingers, gently turning it over and over. "Very clean work, if a bit plain," he observed. "Is it functional?"

"Yes – we think."

The man looked up at Charlie. "You're not sure?"

"It seems to be working fine; at least I can't find anything wrong with it. But the tune seems to be garbled somehow."

"Odd. That should not be possible." The shopkeeper gently lifted the lid to reveal the mechanism; produced a magnifying glass, and examined it for a moment in silence. "Very nice. Very nice, indeed. Definitely custom made, but there's not maker's mark anywhere. The comb is highly unusual, having only - two, four..sixteen tines, tuned in pairs -"

"And therefore the potential to play only eight notes," Charlie finished, a little more forcefully than he'd intended; he knew all this already.

"Exactly. What really interests me, however, is that the cylinder seems to have been hand-pinned."

Charlie blinked. That he hadn't known. "How do you mean?"

The man pointed, holding the magnifying glass over the cylinder. "As you know, the sound of a music box is formed when one of the comb's tines, each of which is carefully tuned, like a tuning fork, is struck and caused to vibrate by one of the bumps on the cylinder, which turns to bring the bumps around to the comb. The bumps themselves are formed by pushing small pins through the brass; it's the pin which actually strikes the comb. On this cylinder, there are many more holes than necessary; only some of them have pins."

Charlie stared. How had he missed this? "So what do you think that means?"

The man blinked at him from behind his glasses. "I'm not sure. My guess is that each hole was originally pinned, and some pins were afterward removed, to make the song you have now. Look." He moved the magnifying glass slightly to focus on the blue-tinted screws holding the mechanism in place. "The cylinder has been removed and replaced."

"That is fascinating," Charlie agreed, squinting at the screws, seeing the telltale scrapes in the metal.

The man finally withdrew the magnifying glass and gave the box a considering look. "You know, if it is indeed playable, it might still be worth something, even not knowing who the maker was, especially if we can reconstruct the original tune. It is a fine piece of workmanship." He moved to turn the key to wind the movement, then stopped. "May I?"

Charlie made a 'go-ahead' gesture. "Please."

They listened, and the shopkeeper shook his head. "I don't understand. Why would someone go to all the work - and it would be a great deal of very fine, very painstaking work - to _vandalise_ this movement?"

Charlie nodded, and there was a moment of pensive silence. "_Are_ you looking to sell it?" the man ventured finally. "I could give you something for it, if just for the curiosity value."

Charlie shook his head and closed the box. "No, thanks, not yet. I'm going to follow this mystery a little further." He paused, and tried to think of what Don would do with this information, what questions he might ask. "Do you have any idea who might custom-make a box like this, or who might have the knowledge to re-pin the cylinder?"

"Companies, yes. Individuals?...It's a rare hobby. I will do some asking around, if you like."

"I'd appreciate it." Charlie dug a business card out of his backpack, and handed it to the antiquarian. "Please do let me know if you think of anything. I'd really like to meet the man who sent this to me."

"I would myself." The man took the card and peered at the small type and the university crest. "A maths professor, are you?"

"Yes, at CalSci."

"Forgive me for saying it, but you don't really look like what I'd expect of a maths professor."

Charlie picked up the box, slung his backpack over his shoulder, and smiled blandly. "We never do."

End Chapter Two.

* * *

You can learn more about how music boxes work at the website for Reuge, a Swiss company which manufactures fine music boxes. w w w . reugemusic . com 

Special thanks to Ice Queen1, SD, sidhe-ranma, sammac, D. Lerious and Anonymous for hitting that "review" button. Stay tuned!


	3. Next steps

**Disclaimer:** _NUMB3RS_ and its associated characters, etc., belong to the show's creators and to CBS, wonderful people whom I have never met and have no connection to. I hope they don't mind me using them here; no legal infringement intended.

**Author's Note:** And here we go with Chapter 3. This is just a short one to keep the story going - there'll be more plot in the next one, promise. :) My thanks to everyone who has taken the time to review and comment, both on the yahoogroup and at fanfiction . net. I always read and appreciate it, and I always take constructive criticism seriously.

And as a bonus for those of you who are faithfully following, I promise you that next chapter I'll give you a link where you can see and hear the music box song (I've got it all written out on manuscript paper; I just have to get it computerized, and my midi program keeps eating it.). :)

**Pitch Perfect - Chapter 3**

by Deichtine

Don gazed blankly at the spreadsheet of transportation expenses, the numbers conveying no information to his tired brain. He and his team had been mired in a fraud investigation for several weeks now, and making no headway. They knew that the financial companies they were investigating were dirty, that they were intimidating their employees - two deaths had occurred which looked suspiciously like object lessons - but they had so far been unable to _prove_ anything, either by the numbers or by the physical evidence. These people were just too good at covering their tracks. He was almost ready to bring Charlie in on the case, though he was reluctant to do so. The AD had quietly let it be known that bringing in Charlie, or any consultant, should only be a method of last resort - they _did_ employ some very good forensic auditors, after all - and Don wanted to give his brother - and himself - a break from their constant collaboration. And, if Don were honest with himself, he'd have to admit that bringing Charlie in likely wouldn't help; the records themselves were faulty, most likely forged. They'd make no headway unless they were able to put their hands on honest records, but with no way to know where they were being kept, if they were being kept, they had nowhere to begin..

"You know, staring at the page isn't going to make the numbers make any more sense."

His partner's voice jolted Don from his preoccupied staring match with the spreadsheet. "Huh?"

Terry sat on the desk, and he leaned back in his chair to look up at her, taking the opportunity to stretch his tired muscles. "You've been distracted all day. Is it that music box thing?" she asked.

He nodded, tossing his pen onto the desk in voiceless acknowledgement that he was getting absolutely nothing done. "Yeah. It's...I don't know. It's like... it's a mystery, you know? I want to be out there, figuring out where it came from, and frankly, this fraud case just does not excite me." He indicated the spreadsheet with an irritated wave of his hand.

Terry ignored the spreadsheet. "Do I detect a note of romanticism underneath that gruff exterior? A yearning for the excitement of the mystery?" she asked, eyebrow arched.

Don furrowed his own brow in answer. "No, it's not that. I'm just worried. I don't know where this thing comes from, or what it represents."

Terry just smiled knowingly, and shook the hair out of her eyes. "I don't believe a word of it. Somewhere in there-" she poked a finger towards his chest "-is a nine-year-old boy, obsessed with mystery stories, who's discovered a trail of footprints and his parents won't let him follow it. Face it, Don, you're a romantic and you know it."

Don looked at her for a moment, ready to object, then shrugged and returned her smile grudgingly. "Okay, maybe that's a part of it. A small part. I admit, I want to be out there with Charlie, asking the questions he won't think of, track down the mystery. But there's this little thing I call my job..." He trailed off and shook his head tiredly.

Terry gave him a sympathetic look. "So Charlie gets to do all the interesting investigative work, while you're stuck here crunching numbers."

"Yeah." Don looked up at her with an ironic laugh. "How did _that_ happen?"

Terry just leaned over, patted him gently on the head, flattening his brush cut, and went back to her desk. Don watched her go, and wondered how it was she always managed to make him feel so silly and so much better at the same time.

* * *

Charlie sat at the desk in the solarium, feeling the morning sun on his face, and looked glumly at the list of names the antiquarian had sent him - by email, which surprised Charlie, though he could think of no good reason why it should. At the top of the list were companies who custom-make music boxes - most of them out of the country - and at the bottom, an even shorter list of individuals the man knew or had heard of who had expressed some interest in tinkering with them. The lists were small, but it would take him at least a whole day to call each of these places, and for what? He was unlikely to find out much, with nothing to go on. He could hear the conversation already in his mind: 

_Hello, this is Dr. Charles Eppes in Los Angeles. Did you by any chance happen to send my brother a systematically depinned music box the other day?_

_Click._

Charlie sighed and shoved the list aside. It could wait. It was time to start into the pattern analysis, at last. It would be much easier, he thought, if he could get the data set translated into numbers. There were a few ways he could go about that. The tune used seven distinct notes (there was the capacity for eight, but from watching the comb as the movement played, he knew the eight note was never actually played); he could simply assign each a numerical value from one to seven. However, the message, if there was one, could be more complicated than that; he would have to have the sound analyzed in terms of its physical properties, too - frequency, amplitude, wavelength...

Also, there were two patterns to worry about now: the original tune, before the pins had been removed, and the post-pin-removal pattern, for though (he supposed) it was quite possible that the box had been tampered with to destroy its information, it was equally possible that the original pattern had been modified in order to create a new pattern, in which the message lay. No, make that three possibilities - the pattern could be only in the pins which were removed, the zeroes of the binary system. Perhaps they all said something.

Initially, he had used graph paper to represent the pattern of pins on the cylinder, painstakingly filling in a square each time a pin was to hit a tine of the comb, but the representation was imperfect; the pins' placement did not always fall in perfect horizontal lines like his graph paper. Their vertical distance determined their timing, and sometimes, though rarely, a note did not fall exactly on the beat, or was held a little longer. Going through the whole process again, this time with a magnifying glass to see where pins had been removed, was not an appealing idea. He had to allow the whole tune to play each time as he could not pause or "rewind" the movement, and given that the song was just under a full minute long, that was a long and wearying task. He'd have to do it eventually, but he just didn't have the energy for it right now.

He would need to use a different transcription system, he decided – musical notation, perhaps. Charlie could read music, to a basic level, at least, and so it would be a logical choice, but he would need help to get it written out properly. He stood up, grabbed a relatively chalk-free jacket from the back of a chair, and, tucking the box under his arm, set out for the university.

End Chapter 3

* * *

Special thanks to AlamoGirl, merryw, sammac, angeleyes46, IceQueen1, SD, pkw, LotRseer3350, sidhe-ranma, and D. Lerious for your reviews! Sammac said it sounds like I know a lot about music boxes, which I guess means I'm a better bluffer than I thought - everything I know I learned from carefully examining my mom's music box and some concentrated web surfing. IceQueen1 asked if it were possible to re-pin the cylinder to get the original melody. Honestly, I'm not sure; I would guess that at this point it would be easier for them to map the points where the pins were and reconstruct the melody through extrapolation, given that they don't have a music-box-mechanic on hand. 


	4. Are those oatmeal cookies?

**Disclaimer:** _NUMB3RS_ and its associated characters, etc., belong to the show's creators and to CBS, wonderful people whom I have never met and have no connection to. I hope they don't mind me using them here; no legal infringement intended.

**Author's note:** Hurray, here comes chapter 4! To make up for Chapter 3 being so short, this one's almost twice as long. This chapter has some Larry for all you Larry fans.

I've placed a link in my author profile to a webpage where you can listen to (in midi) and view the score to the music box song, for anyone who wants to try to 'decode' the message (and there is one). It actually turned out to sound less odd than I expected, definitely patterned within the maj-- wait a minute, I'm going to give it away! Ha ha ha ha. That's the only clue you get. :) I won't promise that it's errorless; I did it all by hand before entering it into the computer and sometimes my _f's_ look like _l's_. And that's the only second clue you get!

By the way, if you think you have found the message, send me a private email at ierneATexciteDOTcom, and I'll publicly praise you in the last chapter for the genius that you are. :)

**Second Author's note:** This chapter also introduces my OC, a linguist by the name of Andrea Gajewski. I am going to try my darndest not to fall into the trap of Mary Sueism with this character (though I admit, she does resemble me a bit), but I need you guys to let me know if she's getting annoying or unbelievable.

**Pitch Perfect - Chapter 4**

by Deichtine

Charlie wheeled his bicycle over to the front office in the physics department, where the departmental secretary was photocopying a tall stack of what looked like vector diagrams. She looked up at the sound of his entry, and smiled warmly when she saw who was entering.

"Charles! Long time no see, stranger. Larry will be so glad you're here - he's been complaining non-stop about the equations he's been waiting for."

Charlie forced a grin, resisting the urge to clench his teeth. It was not the sixty-year-old secretary who irked him - he loved Carol, who was like a grandmother to the grad students and younger faculty and like a mother to the rest. He had forgotten to bring Larry's equations with him. They were finished - he had finished them the day the music box had shown up. But he hadn't yet gotten them off the boards and camera and sent them to Larry. He resolved to avoid his mentor if he could. The music box investigation had completely hijacked his attention.

"Actually, Carol, I'm here to see you. I was wondering if you could book me some time in the Acoustics lab today."

"The acoustics lab? Charlie, you're branching out." Carol had been grandmothering Charlie since his early days as a teen grad student, and kept track of what he was working on, even though he wasn't in her department. She began rummaging in a drawer to find the lab schedule.

"It's just kind of a pet project, a personal thing. I'd only need an hour or so."

She raised her eyebrow at him, obviously curious, and paged through until she found the proper week, then shook her head. "I'm sorry, Charlie, it looks like Adam has the lab booked for the rest of the week. He's been examining the 'possibilities of enhanced spectrographic representation for extremely low frequency sounds'."

"Oh." Charlie frowned. Now how was he to do the recordings? He could do it at home with a computer and a microphone, sure, but he wouldn't be able to get anything near the acoustic purity he wanted, nor could he take other measurements.

"Well, if it isn't just the person I was trying to call," said a voice from the doorway, and Charlie turned around.

"Larry!" he said, with false enthusiasm. Larry just studied him glumly from beneath his eyebrows, his chin resting on his fist.

"You don't have my equations, do you, Charles." It wasn't really a question.

Charlie winced. "Not with me, no. But they _are_ finished. I finished them day before yesterday, I just haven't had a chance to -"

"Day before yesterday? You finished them _two days ago_?" Larry asked incredulously. "And you didn't get them to me?"

"Larry, stuff's been happening - I got sidetracked."

Larry sighed. "You know, Charles, unless the interdimensional creatures have arrived and asked you for a tour of the physics facilities, I don't want to hear it."

Charlie winced even harder. Larry seemed really disappointed. "I'm sorry. I'll email them to you as soon as I get home, I promise. But I can tell you that they completely back up your theory."

"I don't need to hear the excu- what?" Larry blinked.

"You were right. The math completely works for your hypothesis."

Larry, his annoyance forgotten, smiled. "You're sure?"

"Well, there's always the possibility of human error, but to me it looks sound."

"That means I can start readying the paper for peer review."

Charlie nodded, his smile now genuine and warm as he watched the elder professor brightening. "Yes, Larry, it does."

Larry stood there for a moment, smiling broadly, then took a ninety-degree conversational turn without batting an eyelash. "Speaking of sound, what do you need an acoustics lab for?"

"Just a side project. I need to make some good recordings, do some frequency analyses, some spectrographs, that kind of thing."

"Doesn't the FBI have equipment for that?"

"This isn't for the FBI. It's personal." Larry was plainly mystified, but ready to let it pass for now.

"Well, is anything you're recording in the super- or sub-sonic range, or similarly unusual?"

Charlie shook his head. "Actually it's a bit of music."

Larry furrowed his brow. "I can see we're going to have to have lunch so you can tell me about this in more detail. But it sounds like the new phonetics lab would be more than adequate, if you can get in there."

"Since when does CalSci have a phonetics lab?"

Larry shrugged, and yawned, speaking through the yawn. "Since the computer science department started working with the UCLA linguistics department. They've started a massive project in the race to make really useful natural vocal interaction with computers a reality. It's housed in the CS department - you know, the room that used to house the old card-reading supercomputers before they were completely outdated. Carol, are those oatmeal cookies?"

Charlie beamed. "Larry, I could kiss you."

The older man stepped back, hands raised defensively, as though Charlie were ready to make good his threat. "Please don't. But I appreciate the sentiment."

* * *

"All right, people, huddle!" Don clapped his hands once to get his colleagues' attention (loud noises being necessary first thing in the morning, before the coffee really had time to kick in), then led the way to the common area where the boards were set up to display the particulars of the fraud case. Pictures and bios of suspects and people they had questioned were connected by a complicated network of lines. Yellow post-its with comments and notes added colour; pictures of the two murdered men, both high-level employees of the companies under investigation, gave a grisly reminder of the seriousness of this case. 

When everyone was gathered, Don took his place in front of them, hooked his thumbs in the belt loops of his jeans, and began.

"Okay, let's summarize what we know so far. David, you want to tell us about the companies involved?"

David gave a start - Don hadn't given him any warning he'd be helping with the briefing - but to his credit, he nodded and came forward and began without giving any further evidence of being unprepared. Don was sure the younger agent was probably a little uncomfortable, but it was all part of the unobtrusive, unofficial mentoring Don had quietly been giving Agent Sinclair since Merrick had assigned him to his team.

"Ahh, okay. Well, as you know, our investigation centres on the Globecorp corporation, a group of semi-independent investment companies; specifically, we're focussing on the top executives, the president and various vice-presidents of the corporation. We believe that it is these five men who are directly benefiting the most from the fraud scheme, but we have reason to believe that knowledge of the plot runs much deeper, through most of the support staff."

"Why hasn't anyone come forward, then?" one of the newest forensic accountants, a man named Griers, asked. "Surely they can't all be comfortable with being accessories to fraud without even getting a decent payoff."

"Someone did come forward," David answered. "We got our start on this case on the basis of some detailed anonymous tips, which we believe to have come from inside the company. However, we believe the staff are now being encouraged not to talk to us - "

"Intimidation," Don announced, breaking in. "Which leads us to our two murder victims, Marcus Sudre and Frank Rice, both killed by single gunshots to the head, execution-style, in their own homes - in Rice's case, in front of his family. Both were high-level employees of Globecorp. Voiceprint analysis of the tip calls lead us to believe these two were among the ones giving us information, and that they were killed as an object lesson to keep anyone else from talking. So far we have no leads to the killers – probably professional assassins."

David began pointing out pictures on the board, tapping each as he identified them. "Donald Wolfe, president of the company; Ray Chrissom, Miles Crystal, John Fa, and Solomon Lansing, vice presidents of the four major corporate subsidiaries. We've questioned each more than once and found that their stories, though plausible, have minor inconsistencies. Bank records - that we could trace - are showing completely clean, but the spending habits we've observed don't mesh with what they should be capable of given their annual salaries - as impressive as they may be."

"Mr. Chrissom, for example, is a compulsive gambler, who has been seen several times over the last year betting - and losing - huge amounts at casinos in various cities, yet his bank account never registers a hit," Don added.

"Up until now, we've been concentrating on the numbers, looking for definite inconsistencies in the company's financial records and these men's bank accounts, but we haven't found anything there yet," David continued. "We have to assume that the real records, the uncooked books if you will, do exist and are hidden."

"Why do we have to assume it?" another agent challenged from the back of the room. "The first rule of financial crime is never write anything down."

Don nodded. "In small schemes and petty crimes that's generally true. However, these men are, we suspect, amassing millions of dollars between them by siphoning it in tiny amounts from their investors; that money has to be stored somewhere, physically or electronically, and with amounts this big and a scheme this involved, they'd have to be keeping records."

"It's also a trust issue," Terry pointed out. "If there were no records kept, they could easily start fighting among themselves, each accusing the others of cheating him out of his share."

"No honour among thieves," David added.

"So, as of today, our priority is shifting from analyzing the numbers - though we're not going to give up on that angle - to trying to find those records. We need to compile comprehensive files on each of these men and their immediate coworkers and support staff - friends, relatives, anything that might lead us to a good hiding place for these records. It's going to be a huge amount of information," Don said, nodding sympathetically to his teammates, "a lot to sift through. So let's get started."

* * *

It took Charlie about twenty minutes, and two oatmeal cookies, to ride to the building where the CS department was, find a place to lock his bike, and locate the new phonetics lab. When he arrived, the door was closed, and he hesitated. Barging into a room where sensitive sound recordings were being made was never a good idea, and even knocking could disturb an experiment. He peered through the wire-grilled glass of the window set into the door and tried to see if there was an experiment in progress. 

There was - he thought. A brown-haired woman of about thirty was sitting in front of a computer, speaking slowly, word by word, into a microphone. Thin pink wire tendrils were protruding from either side of her mouth, dribbling down her chin as though she had a mouthful of strawberry ice cream. He would have to wait until she looked up at him to get her attention, and so he watched her work. She was pretty in what Charlie thought of as a 'realistic' sense - not a supermodel, but sweet-faced, with inquisitive eyes behind thin-rimmed glasses. Her hair was drawn back from her face in a short ponytail, and locks too short for the ponytail holder fell forward to frame her face softly. Charlie decided he didn't mind having to watch her work for awhile.

Suddenly, moved perhaps by that instinctive sense that prickles the back of the neck when one suddenly realizes that someone is watching, she looked up and saw Charlie standing there, and startled visibly, jumping in her chair. He gave her an apologetic wave and smiled.

Regaining her composure, she blushed, hit a button on her keyboard, saving her work Charlie assumed, and came and opened the door, trailing the pink wires behind her, apparently unnoticed.

"Hello?" She seemed a little flustered by Charlie's sudden and unexplained appearance at her door, and Charlie felt a surge of guilt for having interrupted her.

"I'm so sorry for interrupting you, I know how much I hate it when other people do that to me."

"Don't worry about it. I was almost done anyway. Can I help you? If you're looking for a computer lab, there's one down the hall-"

"No, no." Charlie paused, for a moment unsure how to continue. "Um, I should introduce myself. My name is Charles Eppes, I'm a professor in the Math department."

"Andrea Gajewski," she replied, shaking his proffered hand with a respectable grip. "I'm visiting from UCLA's linguistics department. What can I do for you, Dr. Eppes?" Whatever she had in her mouth didn't seem to be affecting her speech, but Charlie found it incredibly distracting. Again, he had to think a moment before he was able to answer her. _I must look like some sort of idiot,_ he thought.

"Well, um, I was actually wondering if I could beg a favour. I'm looking for a lab with the equipment to make a good-quality recording and give me some readings - you know, frequency, waveforms, some spectrograms, that kind of thing. I tried the physics department's lab, but they're all booked through the week."

She thought for a moment, obviously reluctant. "I don't know. How much do you have to record?"

"Not much, about a minute's worth of playback."

She considered this; then an idea seemed to come to her, and a crafty expression stole over her face. "I might be persuaded - if you'd be willing to do me a favour in return."

_A favour? What kind of favour?_ Charlie thought. He had enough equations on his plate without being drawn into speech synthesis/recognition software logarithms. "Um, what kind of favour?" he said aloud, and she smiled at his obvious discomfiture.

"Don't worry, nothing too onerous or invasive. My work requires that we get speech samples from a wide range of subjects, in order to improve the computer's recognition and decoding capabilities. Basically you'd just be making a few recordings for me, speaking into a microphone. An hour of your time, tops."

Charlie thought about it. His time was precious, but he needed this recording. The pink wires still dangled, distracting him.

"Ah, may I ask..." Charlie started.

"Yes?"

"What do you have in your mouth?"

She looked surprised, then blushed deeply, and turned her head briefly to discretely remove the object and wipe it with a handkerchief from the pocket of her lab coat. When she turned back to him, she showed it to him: a plastic form of her upper teeth and the roof of her mouth, studded all over its concave surface with tiny metal electrodes. It reminded Charlie of the orthodontal appliance he'd had to wear through his teens - minus the electrodes, of course.

"It's an artificial palate. We use them for electropalatography - recording the position of the tongue relative to the palate during speech. I'm sorry, I forgot I was wearing it." She looked profoundly embarrassed, which Charlie found oddly attractive. "Oh God, I look ridiculous with that thing in," she laughed softly.

Charlie grinned back. "I don't think you looked ridiculous at all. Actually, I'm intrigued."

If she had asked him to clarify by what exactly he was intrigued, he would have been hard pressed to answer.

End Chapter 4.

* * *

Again, huge thanks go out to my beta-readers. You guys rock. 

For a fascinating (to me anyway, but then again I'm rather odd) look into electropalatography, the world of acoustic phonetics and the various devices used by linguists and speech pathologists to measure various aspects of speech, have a look at the UCLA Phonetics lab web site at ht tp/ ww w. linguistics. ucla. edu / faciliti / uclaplab. ht ml (click on 'facilities'). This link is also in my author profile. The artificial palate they picture doesn't have pink wires, but the one in the picture in my _Encyclopedia of Language_ does, and that was my original model. :)

Special thanks to dedletrbox, sammac, pkw, SD, Zubeneschamali, Stealth Dragon, CrystalMak, Alamo Girl, and D. Lerious for your reviews! They make me happy. :D


	5. microphones, music, and integrity

**Disclaimer:** NUMB3RS and its associated characters, etc., belong to the show's creators and to CBS, wonderful people whom I have never met and have no connection to. I hope they don't mind me using them here; no legal infringement intended.

**Author's note**: I am delighted to say that at least one person is hot on the trail of finding the musical message - I'm delighted to say that there is actually someone trying! And she has picked up on some clues I hid in Chapter 4 - hurray! Sorry for the delay with this chapter. I'm having a bout of 'writer's malaise' and had to kind of churn it out. Please don't forget to review when you're done; I'm needing the encouragement lately.

This chapter features some Don-Margaret warm fuzzy memories that get a little cheesy. You have been warned.

BTW: in case you're wondering, we see the piano hanging out in the background of the Eppes' living room in more than one episode - I first noticed it in "Prime Suspect".

Unfortunately this chapter has not been as thoroughly beta-read as I haven't given my betas enough time to get back to me before I post this, but I'm going out of town for the weekend and wanted to get this up, as it's been almost a month (criminal, I know).

UPDATE JUNE 29/06: This chapter/story was written before the episode aired in which we learn about Margaret being a pianist and teaching the boys. WHO CALLED IT? Booyah.

**Pitch Perfect **- Chapter 5

by Deichtine

Andrea helped Charlie position the microphone over the music box's mechanism, and showed him through the various features of the recording program. She had been delighted and mystified when Charlie explained the music box and how it had mysteriously come into and hijacked his life. She seemed thrilled by the mystery, and her initial reluctance to allow a personal project from someone outside the department to use her lab resources had evaporated. Her own experiment paused for the moment, she sat quietly and listened as Charlie played the box into the computer program, watching the rise and fall of the waveforms as they appeared on the screen.

"Wow, that's..." Andrea searched for a word, then shrugged. "...Really weird."

"Yeah," Charlie said, with a close-lipped smile and a raise of his eyebrows. "You're telling me."

'So you think there's a message encoded in there?"

"The more I listen to it, the more certain I am that there is. For example, listen to this part near the end..." he moved the cursor back to the appropriate point and played it back. "There's a definite pattern there - one note, then two notes together, and it repeats on different pitches - bah bum bum, bah bum bum."

Andrea thought for a moment. "Would it make it easier if you could see the notation?"

Charlie nodded. "Actually, that's my next step - find someone familiar enough with music to write it out for me. Which should be interesting, given that we don't have a music department."

Andrea gently elbowed Charlie over to take control of the computer. "Never mind that." She clicked on various menus, entered values in certain pop-up windows, and hit 'Enter'. Suddenly the screen filled with musical notes, neatly printed in the treble clef. "You might have to double check it, especially the timing, but that should save you some time."

Charlie grinned. "Thanks! I had no idea we could do that."

Andrea shrugged and smiled. "This audio program was initially designed more for musicians recording their work than for linguists, but it turns out our needs are not that different. I seldom have any reason to use that feature, but it's come in handy a few times, with tonal languages. For really complicated chords and instruments with a lot of reverberation that feature actually doesn't work that well, but your music box produces near-pure tones, so it's fairly simple."

Charlie stared at the music, the pattern he had noticed even more apparent when viewed on the stave. He was fascinated. "Can we print this off?"

Andrea was already working. "Done. I'm also saving the music and the waveforms and the rest to image files for you. What's your email?" Charlie gave it to her, and leaned back to think about what he'd seen. So far the spectrographs and waveforms hadn't immediately 'spoken to him'; meaningful patterns had not jumped out at him shouting "here I am", but he was more hopeful, now that he had something concrete to work with.

Andrea closed down the program, and Charlie extricated the music box from the recording equipment surrounding it, then stood up to go, a little regretfully.

"Thank you again, Dr. Gajewski, you've been a huge help."

She grinned, and tucked a stray lock of hair behind her ear. "It's Andrea. Are you ready to do some speaking for me?" She asked, indicating her computer at the front of the room.

Charlie blinked. Speaking? Then he remembered the deal - in return for the use of the equipment, he had to be a vocal guinea pig for Andrea. He moved over to the other computer, where everything was all set up.

The artificial palate she'd been using when he first arrived was sitting on the table near the keyboard, and he regarded it a bit uncomfortably. What had he gotten himself into?

She saw where he was looking, and laughed aloud, a gentle, genuine laugh. "You don't have to use anything like that, don't worry. We don't want to scare you off on your first day." She picked up the palate and began coiling its wires. "Besides, you need to have them custom made, and they're pretty expensive. What I need today requires nothing more than a man and a microphone."

Charlie grinned. "Well, looks like you've got both right here."

* * *

Don tugged at his tie and straightened his suit, and absently tried to smooth away with his hand the wrinkles that had set in during his forty-minute commute. Beside him on the stylish leather reception-area couch, Terry was reviewing her notes from the last time they had questioned Ray Chrissom. Across the room, on the far wall, the word "Globecorp" was spelled out in large polished brass letters. 

"Agent Eppes?" the receptionist called. "Mr. Chrissom can see you now."

Don and Terry rose as one, and entered the Executive Vice President's inner sanctum.

Chrissom's office was warmly decorated, with rich, polished woods and tasteful knickknacks and _objets d'art _- antiques, no doubt - strategically placed for maximum effect. Sunlight streamed in from windows set into two walls, and a water cooler quietly burbled in one corner.

"Mr. Chrissom." Handshakes all around.

"Agent Eppes, a pleasure to see you again. And this is...?"

"Special Agent Terry Lake, my partner."

"Enchanté. Agent Eppes, is it too much to hope that you come bearing news that our corporation has been cleared of any wrongdoing?"

Don shook his head. Chrissom was the kind of polite, outgoing, buddy-buddy businessman that set Don's teeth on edge. In some ways he almost preferred the gang leaders, robbers, terrorists and murderers he dealt with on the streets - at least they were honest about their dishonesty, and there was no need to maintain polite fictions.

"I'm sorry, but I'm afraid we have a few more questions."

Chrissom sat down behind his desk and leaned back into the high-backed chair. "Frankly, Agent, I don't know if there's anything more I can tell you. I'm a very busy man - "

"Yes, and we appreciate your cooperation on this very serious matter," Don interrupted, and retrieved a notepad from his inside breast pocket. "Now, the last time we spoke, two weeks ago, we talked about Globecorp's financial records. This time, I'm afraid the matter is more - " he stopped, looking for the right word.

"Grave," Terry supplied.

Don nodded. The perfect word. He set the notepad down, and opened the file he had brought in with him. "Marcus Sudre and Frank Rice," Don said, tossing the crime scene photos onto the desk before Chrissom.

For just the tiniest fragment of a second, Don thought he caught a flicker of genuine reaction on the man's face - a darkening of the eyes, a tightening of the lips, an added tension in the jaw; what it meant, he couldn't say. It was replaced almost immediately by a mask of sorrowful regret, an expression calculated to blandly say, _What a pity_.

"What a shame," Chrissom said, glancing at the photos, then turning his eyes away with proper decency. "Such a waste," he added. "They were bright young men, and would have gone far with this company. I certainly hope you're able to find the people who did this. Do you have any leads?"

"We're following up on some tips," Don answered non-committally. "How well did you know the victims, Mr. Chrissom?"

"Frank Rice I barely knew at all. He worked in a different area - I think John Fa's office. But Marcus..." Chrissom's eyes grew shadowed again, and this time Don was almost inclined to believe there was an element of sincerity hiding there. "...Marcus worked with me. Now there was a man who was going places. Hard worker, real eye for detail, killer instincts when it came to investments."

"What exactly did Mr. Sudre do for you?"

"He was an investment consultant, worked wtih some of our best clients. He's going to be very difficult to replace; he had built up rapports with the clients, and they trusted him."

"Mr. Chrissom," Terry broke in, "did Marcus have any enemies? Dissatisfied clients, maybe?"

"Rivals within the office?" Don added.

Chrissom shook his head no. "No, I can't think of anyone. What you need to understand is that Marcus had a reputation for honesty, for integrity. He had this old-fashioned sense of personal honour; he was sincere almost to a fault. Everyone loved him, everyone respected him."

Terry seized on this. "To a fault - do you think this sincerity was part of what got him killed?"

Chrissom blinked. "I really couldn't say. I guess if he told the wrong truth about the wrong people - but I'm afraid you're talking to the wrong guy about that." He shifted in his chair, checked his watch.

"Were you ever aware of Marcus being troubled by his work here? Did he ever confide in you?" Don asked.

"Not really. I was his superior, and, though we got along well enough, we weren't personally close. Now, Agent Eppes, I'm afraid I have a conference call in five minutes that I really need to prepare for." He stood up, and Don and Terry followed suit.

"One last question, Mr. Chrissom," Don said. "You understand I have to ask. Your whereabouts at about six o'clock Thursday evening?"

Chrissom looked insulted, but he let a breath out his nose and thought about it. "Yes, I suppose you would have to ask. I was having supper at home with my wife."

"Can anyone else verify that?"

"It was just me and my wife. But if you like I can call her and she'll tell you I was there."

"That won't be necessary, thank you." Again, handshakes all around. Don took a last look around the office, and then looked Chrissom straight in the eye. "If there's anything, anything that you think we should know, you have my card."

Chrissom broke the stare first. "Yes, of course."

Later, as they drove back towards the FBI building, Don tapped his hand with nervous energy on the steering wheel. "There was something he wasn't telling us. I'm sure of it. He was holding back."

"I agree. Those pictures frightened him, I think."

"Bastard."

"Yeah."

* * *

When Don arrived at the Eppes house that evening, he found his brother in the living room, ensconced on the floor by the coffee table, his legs folded beneath him and his dark curls swinging gently back and forth as he turned his head to compare the information on various pieces of paper laid out in front of him. His laptop was open in front of him. Alan was nowhere to be seen. 

Charlie loked up as his brother entered and smiled a distracted greeting. "Hey, Don."

"Hey, Charlie. Dad home?"

"Bowling."

"Really?" Don dropped his briefcase on a chair and pulled off his suit jacket.

"Yep. He seems to have taken to it." Charlie was searching through his pages and finally came up with a piece of printed sheet music. "I'm glad you're here. Want to do me a favour and try playing this? I need to be sure it's accurate."

Don took the sheet and glanced it over. "What's this?" His case, and the day's interviews, were still very much on his mind, and he had entirely forgotten about the music box.

"It's a fugue I composed for Dad's birthday," Charlie said with friendly sarcasm, and laughed at Don's raised eyebrows. "No! It's the song from that music box of yours."

"Oh," Don said. "Why don't you play it?" Charlie knew the basics of the piano, but had never learned to play well; he never had the patience for the practice it required.

"Two reasons. One, you're the pianist in the family, not me. Two, I've been listening to that song backwards and forwards for three days running and I couldn't be sure that I was playing what was on the page, and not what was in my head."

"Oh." Don laid his jacket ofver the back of the sofa and moved over to the piano. "You realize it's been years since I played,' he warned as he sat down and gently raised the lid. Automatically, his right hand sought out middle C.

"It's like riding a bike. You never forget."

"Yeah, says the man with the eidetic memory," Don returned, and Charlie just grinned and shrugged.

Gently, Don started tapping a beat on his knee with his left hand, mentally counting. Slowly, carefully he picked out the little melody, only tripping up once or twice, then played it though a second time with more confidence as his kinetic memory began to return to him.

"Okay, thanks Don, that's good," Charlie called, and Don set the sheet music aside, but didn't get up. He brushed his fingers gently over the keys, feeling the familiar smoothness of the faux ivory. The piano was still relatively in tune, and its sound brought him back to when his mother had sent his father out for a walk with the three-year-old Charlie and sat her ten-year-old firstborn beside her on the piano bench and began teaching him how to play.

As the boys grew, and Charlie's special needs began to take more and more of his parents' attention, their mother always made it a point to spend time with Don at the piano. When he outgrew her lessons and went on to other teachers, she still stayed near as he practiced, singing along or lending helpful, annoying advice - he could hear her now, calling from the kitchen where she was drying dishes: "Watch your F sharp, Donny!"

"Play something, Don," Charlie said softly.

Don reached into the piano bench, and pulled out the first thing his hand encountered - a bok of intermediate-level piano solos, well worn from many trips in his knapsack. It fell open as he put it up on the piano to Beethoven's "Moonlight Sonata", and softly, gently, he began to play, his mind filling with memories even as the tension began to bleed out of his shoulders and neck. His fingers, once again confident, faltered only rarely. He was only barely conscious of reading the notes - it was as though the notes on the page went straight from his eyes to his fingers without bothering to go through his conscious mind.

When he finished and turned around, he found Alan standing there in the open doorway, unwilling to close the door lest he interrupt the music. His eyes were glistening as he stared at his son.

"Thanks, Don," Charlie said, after a moment's pause, breaking the spell. Alan came the rest of the way in, and Don closed the piano.

"That was beautiful, Donny," Alan said. "You should - " he cleared his throat. "You should play more often."

"Yeah, maybe," Don replied softly, then shook himself and turned back to his brother. "So, what have you found with the music box?"

Charlie shook his head and shifted his legs under the coffee table. "Not much. I've learned that the song has been deliberately modified from the original, and the notes aren't completely patternless. Not many companies custom-build music box movements, and this is apparently very nice work. I have a list of possible companies, but I haven't started calling them yet. I wanted to get started on pattern analysis of the song itself."

"Any leads on what the message might be yet?"

Charlie stared at him, his eyes wide and incredulous. "Don, do you have any idea how difficult a ciphertext-only attack is? And I don't even know for sure that I have the intended ciphertext. Aside from a gut feeling that these notes are not random, and some mathematical tools, I have nothing to go on. I have, what, five or six lines of music - that's a very small sample to build an attack from. If I had some cribs to try, maybe that might help, but without them, well, it could be weeks if I'm lucky, maybe months, maybe never."

"But Charlie, you're great at finding patterns."

"Well, though I appreciate your confidence in me, it's not that simple. It's not just a matter of finding the pattern. Rather, what does the pattern signify? Music by its very nature follows distinct patterns - just think of the Sonata you just played - and any pattern I find in this could conceivably be merely residue of the original song. Or, it could be meaningful, but I'd stll need to find the equations governing it. You can't just pull this stuff out of the air, Don."

Don nodded apologetically. "Sorry. I guess I kind of take it for granted that, given a chalkboard and a piece of chalk, you can do pretty much anything once you get started."

Charlie grinned tiredly. "Thanks, but I wish. So how's your case coming?"

Don stood up, stretched, and fell into an armchair. "Slowly. I feel like I'm beating my head against a wall. I know these guys are dirty. I know they are. But the evidence is just not coming."

"Would some iced tea help?" Charlie levered himself up from the coffee table, and winced as his foot began to throb with pins and needles.

"That would be heaven."

Alan turned on the TV and sat back, letting music boxes and fraud cases flow past him. His family, all four of them, was together there, and he was content.

* * *

End Chapter 5 

Learn about ciphertext-only attacks at the Wikipedia (link in my author profile).

Special thanks to kippling croft, Stephanie519/SD, Crystal Mak, Alamo Girl, Whyte Star, LotRseer3350, and umino-gaara for taking the time to review, as well as to those of you who chose to email me personally. I really appreciate all your comments, especially when I'm lacking in energy - your comments give me the kick in the pants I need to get writing again. I send virtual flowers to all of you. :)


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